Either the drain or the line could be clogged.

Also, infinity edge basis are NOT plumbed in any consistent manner. This means, without seeing the inlets, returns, valves and pump(s), AND having some idea how all of that is connected, there's no particular way to answer your question.

Common problems -- not necessarily YOUR problem -- include:
  • clogged drains
  • CRACKED and damaged covers (from suction + excess debris)
  • plugged suction lines (from cracked covers)
  • clogged pump impellers (debris, again)
  • cracked / air-leaking suction lines
  • stuck / badly placed check valves
  • other valves wrongly closed / opened
  • pump not priming for whatever reason
  • electronic controls mis-configured or not operating well.
  • etc.

Just FYI, infinity edges deliver a WORLD of problems to pools. To operate well . . . over a period of years . . . they require
  • expert installation . . . OF THE SHELL AND FOUNDATION,
  • expert plumbing,
  • expert control configuration, AND
  • consistent maintenance and cleaning.

Few, if any, pool builders can deliver on all of those. I have been in close contact for several years now with a pool service guy who mostly works on pools that cost upwards of $100,000 each and are built by the "best luxury pool builder in the Southeast".

To date, he has never encountered a "luxury" pool that does NOT have SERIOUS design or installation problems.

What I've learned is that the most successful pool builders universally seem to be
  • great at sales,
  • good at aesthetic design,
  • fair at 'fit and finish', BUT
  • mediocre at operational design, AND
  • mediocre to poor at structure and plumbing!

Bottom line?

Most of the time, if you purchase a 'luxury' pool, you are buying a long-term high-maintenance and high-expense home feature that you can only escape by moving.

For what it's worth, SIZE is not a problem. It's possible to design VERY simple, VERY reliable LARGE pools. But add 'features': electronic controls, variable lighting, fountains and slides, multiple 'pools' (ie, connected spa / basin / kiddie puddle) and so on, and the reliability almost always tanks!